Roll wrap preventer



Nov. 16, 1965 s. H. FOWLER ETAL 3,217,355

ROLL WRAP PREVENTER Filed Nov. 4, 1963 INVENTORS S. H. FOWLER J.D. VEITCH ATTOR Y United States Patent O 3,217,355 ROLL WRAP PREVENTER Spencer H. Fowler, Tanner, and John D. Veitch, Decatur, Ala., assignors to Monsanto Company, a corporation of Delaware Filed Nov. 4, 1963, Ser. No. 321,315

1 Claim. (CL 18-1) This invention relates to the handling of thermoplastic yarn and more particularly to the preventing of stray filaments of a tow from wrapping around a roller during a stretching process.

One step in the texturizing of continuous filament tows is the stretching process. After the tow has been formed and washed, it is desirous to anneal it in order to prevent fibrillation. This may be done by continuously bathing the tow in hot water or steam and then stretching it between rollers. The tow comes out of this bath hot and wet and, due to this condition, the filaments have a tendency to stick to the rollers; therefore, if a filament breaks in this stretching process, it wraps around the rollers. These wraps, once started, build rapidly and collect additional filaments by tearing them away from the tow. This build-up must be removed, thereby causing interruptions in the operation, poor fiber quality and constituting a hazard for the operator attempting toremove them. Therefore, an object of this invention is izing synthetic continuous filament tows, the stretching to alleviate these undesirable conditions by preventing filaments of the tow from wrapping around the stretching rollers.

Another object of this invention is to provide a set of rollers with a tow guiding device.

A further object of this invention is to provide a set of rollers with adjacently disposed rods which induce cohesion among the filaments comprising the tow.

The invention is best understood by reference to the following description and accompanying drawing wherein:

FIGURE 1 is an isometric illustration of a preferred arrangement of the rollers and the anti-wrap rods;

FIGURE 2 is a front elevation view of a roller and the anti-wrap rod; and

FIGURE 3 is a front elevation view of a roller and anti-wrap rod showing the anti-wrap rod preventing a broken filament from being wrapped around the roller.

One embodiment of this invention contemplates using stretching rollers in close association with anti-wrap rods. The anti-wrap rods are of any suitable abrasion-resistant material, such as stainless steel, and are placed in light contact with a tow, parallel with the rollers and immediately beyond the point at which the tow leaves the roller. The anti-wrap rods are cantilevered from a wall (not shown) of the parent machine.

After the tow is bathed in a hot liquid, such as steam or hot water (not shown), where it is softened and is prepared for the stretching process, the tow is then advanced through a series of rollers where it is elongated a predetermined amount by driving each roller at a faster rate than its predecessor. Occasionally, a filament, a plurality of which comprise the tow, becomes weakened by the heating and stretching and breaks. Since all of the moisture which the filaments received from the bath has not evaporated when the tow is being stretched, the retained moisture tends to act as an adhesive agent, thereby binding the broken filaments to the rollers. If the tow were dry, the broken filaments would have no tendency to stick to the rollers since the rollers generally have a polished surface. Once a broken filament makes a complete turn on the roller and engages the incoming tow, the filament rapidly builds up, thus wasting fiber and interfering with the stretching process.

To retard and prevent filament wrapping while texturrollers are provided with anti-wrap rods or bars. As the tow leaves the roller, it tangentially touches the anti-wrap bar thereby trapping a length of the broken filament between the main body of the tow and the anti-wrap bar. The cohesive force between the broken filament and the tow which is produced by the anti-wrap rod forcing the broken filament into the tow is greater than the adhesive force between the broken filament and the rollers. Therefore, as the tow moves across an arc of the anti-wrap bar, it carries the broken filament therewith, thereby breaking the adhesive bond between the broken filament and the roller so that the broken filament is drawn back into the body of the tow. Since the broken filament must be stripped from the roller before the roller has carried the end of the filament around the roller and into a position of engagement with newly received tow, the antiwrap bar is to be spaced a distance (measured along the path traced by the tow) from the roller which is less than the length of the periphery of the roller from where the tow tangentially leaves the roller to where the tow initially tangentially contacts the roller. In other words, the antiwrap bar is no further from the roller than the circumferential length of that portion of the roller which is not in contact with the tow. This distance is more simply calculated by subtracting the length of contact between the tow and the roller from the circumference of the roller. If the anti-wrap rod were not so positioned, the broken filament would be caught beneath the newly received tow, thereby preventing the anti-wrap bar from removing it from the roller.

This invention is illustrated in connection with the accompanying drawings in which the figures are illustrative of the preferred embodiment of the invention.

As shown, the tow 10 which has been heated by a steam or hot water bath (not shown) is stretched by rollers 11, 12, 13, and 14 which are mounted on shafts 15, 16, 17 and 18, respectively, and are turned by any conventional means (not shown). Each roller travels at a speed which is greater than its predecessor, thereby stretching the tow a predetermined amount between each pair of rollers. As the tow 10 is being stretched, some filaments 19 of the tow 10 may break and adhere to one of the rollers (FIGURE 3). If the filament 19 is not quickly removed from the roller 14, the filament 19 attracts other filaments thereby building a pile of filaments on the roller 14.

Anti-wrapper rods 21, 22, 23, and 24 are in juxtaposition with rollers 11, 12, 13 and 14, respectively, so that when the tow 10 tangentially leaves the surface of the rollers, it passes over anti-wrap rods. When a broken filament becomes separated from the tow 10 and adheres to the surface of the roller 14 (this particular roller being selected for purposes of illustration) the anti-wrapper bar 24 prevents the roller 14 from carrying the filament 19 through a rotation by breaking the adhesion bond between the roller 14 and the filament 19. In FIGURE 3, a broken filament 19 has separated from the tow 10 and has adhered to the roller 14. As the tow 10 moves in the direction of the arrow, the broken filament 19 assumes a position 19a and passes over the anti-wrap rod 25, thereby being forced back into the tow 10. The cohesion between the broken filament 19a and the other filaments which comprise the tow 10, being frictionally greater than the adhesion between the broken filament 19a and the roller 14, causes the broken filament 19a to be lifted from the roller 14. After the entire length of the broken filament 19a, which has been previously separated from the tow 10, broken filament 19a assumes position 19b and is once again an integral part of the tow While the preferred embodiment of this invention has been disclosed, it is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined by the appended claim.

We claim:

An apparatus for guiding and advancing a wet tow of continuous filamentary material having broken filaments appendant thereto through a stretch zone comprising a plurality of rotating stretch rollers for guiding and advancing a tow along a predetermined path, said path being defined by said rollers and being substantially straight between rollers, and stationary bar being mounted in juxtaposition with each of said stretch rollers and located in the angle formed by each roller and the tow tangentially leaving the same, said bar tangentially contacting and frictionally engaging said tow at a distance from said roller which is less than the distance of that portion of the periphery of said roller which is free from contact with said tow, said stationary bar being adapted for realigning said broken filaments being appendant to said tow with the body of said tow.

References Cited by the Examiner UNITED STATES PATENTS 2,046,930 7/1936 Schrenk 188 2,289,232 7/1942 Babcock 1s-s 2,455,173 11/1948 Hitt 18-8 2,527,502 10/1950 -Sirnison et a1. 65-4 2,611,923 9/1952 Hume 188 XR 2,630,976 3/1953 Keight.

2,962,753 12/1960 Hale etal. 18--2 2,987,761 6/1961 Schuller et al. 1s s XR FOREIGN PATENTS 780,620 8/1957 Great Britain. 784,535 10/1957 Great Britain.

WILLIAM J. STEPHENSON, Primary Examiner. 

